Abstract
A 63-year-old woman complained of a growing neck mass. Sonography revealed a solid and cystic mass in the right thyroid lobe. Color Doppler study and computed tomography revealed anechoic cystic portions within the thyroid nodule to be a pseudoaneurysm arising from the right inferior thyroid artery. The only identifiable risk factor was a past thyroid needle biopsy performed approximately 5 years previously according to the patient's recollection. Right lobectomy was performed and the pseudoaneurysm was treated without complication.